Calculator rule



FIG. 1 is a bottom front perspective view of a calculator rule;

FIG. 2 is a front elevation view of the calculator rule of FIG. 1;

FIG. 3 is a bottom plan view of the calculator rule of FIG. 1;

FIG. 4 is a top plan view of the calculator rule of FIG. 1;

FIG. 5 is a left side elevation view of the calculator rule of FIG. 1;

FIG. 6 is a right side elevation view of the calculator rule of FIG. 1;and,

FIG. 7 is a back side elevation view of the calculator rule of FIG. 1.

The ornamental design for a calculator rule, as shown and described.